Numerical simulations of hypersonic flows in chemical nonequilibrium
File(s)
Author(s)
Margaritis, Athanasios T.
Type
Thesis
Abstract
Hypersonic flows are a critical aspect in a variety of aerospace applications. Experimental testing and numerical simulations are necessary for successful mission design. Challenges of hypersonic flow modelling arise due to the interconnected physical phenomena involved.
This thesis presents the development of numerical tools for high-fidelity simulations of reacting hypersonic flows, including finite-rate chemistry. This work focuses on developing a solver for compressible fluid dynamics and extending it using several numerical techniques to improve its accuracy and performance in hypersonic flow simulations. Furthermore, the solver was linked to the modular external open-source library Mutation++ which provides a variety of physicochemical properties for several multicomponent gas mixtures.
The numerical tools developed were verified against results in the literature. The effects of chemical nonequilibrium were identified and examined in several configurations. Results are presented for canonical test cases, such as flat-plate boundary layers with various thermochemical models, with excellent agreement with the literature. Moreover, the capabilities of the numerical tools were tested in complex new configurations, such as supersonic shock--boundary-layer interaction and jet in a hypersonic cross-flow, after implementing an artificial-diffusivity shock-capturing scheme.
This research was extended using these computational tools integrated into general methodologies. An investigation was performed on roughness-induced transition, using machine-learning techniques to quantify the effect based on a generated dataset. Furthermore, the numerical solver was used within a matrix-free implementation of a mathematical framework for efficiently simulating N-periodic flow configurations.
The developed numerical tools provide an ideal starting point for further research. Preliminary work has been done to develop an adjoint-based solver coupled to the forward non-linear and linearised versions. This work provides a valuable contribution to the field of numerical simulations of reacting hypersonic flows and paves the way for further research in a variety of reduced-order modelling, optimisation, and control applications, using the tools developed.
This thesis presents the development of numerical tools for high-fidelity simulations of reacting hypersonic flows, including finite-rate chemistry. This work focuses on developing a solver for compressible fluid dynamics and extending it using several numerical techniques to improve its accuracy and performance in hypersonic flow simulations. Furthermore, the solver was linked to the modular external open-source library Mutation++ which provides a variety of physicochemical properties for several multicomponent gas mixtures.
The numerical tools developed were verified against results in the literature. The effects of chemical nonequilibrium were identified and examined in several configurations. Results are presented for canonical test cases, such as flat-plate boundary layers with various thermochemical models, with excellent agreement with the literature. Moreover, the capabilities of the numerical tools were tested in complex new configurations, such as supersonic shock--boundary-layer interaction and jet in a hypersonic cross-flow, after implementing an artificial-diffusivity shock-capturing scheme.
This research was extended using these computational tools integrated into general methodologies. An investigation was performed on roughness-induced transition, using machine-learning techniques to quantify the effect based on a generated dataset. Furthermore, the numerical solver was used within a matrix-free implementation of a mathematical framework for efficiently simulating N-periodic flow configurations.
The developed numerical tools provide an ideal starting point for further research. Preliminary work has been done to develop an adjoint-based solver coupled to the forward non-linear and linearised versions. This work provides a valuable contribution to the field of numerical simulations of reacting hypersonic flows and paves the way for further research in a variety of reduced-order modelling, optimisation, and control applications, using the tools developed.
Version
Open Access
Date Issued
2023-09
Date Awarded
2024-03
Copyright Statement
Creative Commons Attribution NonCommercial NoDerivatives Licence
Advisor
Schmid, Peter J.
Sponsor
United States. Air Force. Office of Scientific Research
Grant Number
FA9550-18-1-0127
Publisher Department
Department of Mathematics
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)